How to get function body text in JavaScript?

Since you want the text between the first { and last }:

derp.toString().replace(/^[^{]*{\s*/,'').replace(/\s*}[^}]*$/,'');

Note that I broke the replacement down into to regexes instead of one regex covering the whole thing (.replace(/^[^{]*{\s*([\d\D]*)\s*}[^}]*$/,'$1')) because it's much less memory-intensive.

NOTE: The accepted answer depends on the interpreter not doing crazy things like throwing back comments between 'function' and '{'. IE8 will happily do this:

>>var x = function /* this is a counter-example { */ () {return "of the genre"};
>>x.toString();
"function /* this is a counter-example { */ () {return "of the genre"}"

var entire = derp.toString(); 
var body = entire.slice(entire.indexOf("{") + 1, entire.lastIndexOf("}"));

console.log(body); // "a(); b(); c();"

Please use the search, this is duplicate of this question